This research is intended to develop two batteries of behavioral, information-processing, tests. One test is intended for screening purposes for field evaluation of toxicological health hazards. The second battery is intended for medical diagnostic and research use. Both batteries will be applicable over the age range of at least 5-65 years. New, rigorous, independent concepts of validity, sensitivity, and severity of effect are introduced as the basis for test development. Reliability and standardization for critical populations will be handled in the conventional manner.